DRYING EXPERIMENTS WITH ALO(OH) SUSPENSION OF HIGH PURITY AND FINE PARTICULATE SIZE TO DESIGN AN INDUSTRIAL SCALE DRYER

2000 ◽  
Vol 18 (3) ◽  
pp. 759-776 ◽  
Author(s):  
T. Szentmarjay ◽  
E. Pallai
TAPPI Journal ◽  
2015 ◽  
Vol 14 (11) ◽  
pp. 689-694
Author(s):  
QINGZHI MA ◽  
QI WANG ◽  
CHU WANG ◽  
NIANJIE FENG ◽  
HUAMIN ZHAI

The effect of oxygen (O2)-delignified pine kraft pulp pretreatment by high-purity, thermostable, and alkaline-tolerant xylanases on elemental chlorine free (ECF) bleaching of O2-delignification kraft pulp was studied. The study found that xylanase pretreatment preserved the intrinsic viscosity and yield of O2-delignified pulp while causing about 7% of delignification with high delignification selectivity. The xylanases with high purity, higher thermostability (75°C~80°C) in highly alkaline media (pH 8.0~9.5) could be applied on an industrial scale. Pulp pretreatment by the high-purity, thermostable, and alkaline tolerant xylanases could improve pulp brightness or reduce the chlorine dioxide (ClO2) consumption. In a D0ED1D2 bleaching sequence using the same amount of ClO2, the xylanase-pretreated pulp obtained a higher brightness (88.2% vs. 89.7% ISO) at the enzyme dose of 2 U/g pulp; or for the same brightness as control (88.2% ISO), the ClO2 dosage in the D0 stage was reduced by 27%, which represents a 16% savings in total ClO2 used for bleaching.


2020 ◽  
Vol 74 (10) ◽  
pp. 776-778
Author(s):  
Stefan Krawielitzki

Swiss-based AVA Biochem AG is the global leader in the industrial production and sale of the bio-based platform chemical 5-hydroxymethylfurfural (5-HMF), a renewable and non-toxic alternative to a range of petroleum-based materials. 5-HMF has a broad range of applications in the chemical, pharmaceutical and food industries. Since 2014 AVA Biochem has been producing high-purity 5-HMF for research purposes and specialty chemicals markets, as well as technical-grade 5-HMF for bulk chemistry applications. AVA Biochem's own R&D department also develops the downstream chemistry of 5-HMF and thus opens the door to biobased furan chemistry on an industrial scale.


2018 ◽  
Vol 34 ◽  
pp. 02011
Author(s):  
M Dewika ◽  
M Rashid ◽  
M.R Ammar

This paper presents on the performance of a retrofitted multicyclone system, which aims to increase the collection efficiency of PM2.5 (i.e. particulate size fraction ≤ 2.5 μm) emission. The multicyclone was retrofitted by extracting 15% and 20% of the total volumetric air flow rate at the dust hopper of the unit using an additional Induced Draft Fan. The total collection efficiency with and without the extraction was measured at various air volumetric flow rates and particulate mass inlet concentration. The results showed that there was a reduction of 12% to 54% depending on the inlet concentration of PM2.5 emission in the stack with compared to without extraction increasing the collection efficiency of the retrofitted multicyclone. The finding suggests that a simple technique of applying gas extraction at the dust hopper of a multicyclone as reported in this study able to increase the overall performance in fine particulate collection.


2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Yohei Yomogida ◽  
Takeshi Tanaka ◽  
Minfang Zhang ◽  
Masako Yudasaka ◽  
Xiaojun Wei ◽  
...  

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1130 ◽  
Author(s):  
Katarzyna Leszczyńska-Sejda ◽  
Grzegorz Benke ◽  
Mateusz Ciszewski ◽  
Michał Drzazga

Technology used to produce high purity anhydrous rubidium perrhenate on an industrial scale from high purity perrhenic acid and rubidium nitrate by the ion-exchange method is described in this paper. This material is dedicated to catalyst preparation, therefore, strict purity requirements have to be fulfilled. These are satisfied by combining rubidium ion sorption on an ion exchange column and the subsequent elution of the high purity perrhenic acid solution, followed by crystallization, evaporation, purification, and drying. In the current study, rubidium and rhenium contents were found to be 22.5 wt.% and 55.4 wt.%, respectively, while contaminations were as follows: <2 ppm As, <2 ppm Bi, <5 ppm Ca, <5 ppm Cu, <3 ppm Fe, <10 ppm K, <3 ppm Mg, <5 ppm Mo, <2 ppm Na, <5 ppm Pb, and <3 ppm Zn.


2017 ◽  
Vol 79 (6) ◽  
Author(s):  
M. Dewika ◽  
M. Rashid ◽  
N. Hasyimah

Cyclone is one of the most commonly used particulate dust collectors in industries. It employs centrifugal force generated by a spinning gas stream to separate the particulate matter from the carrier gas. However, cyclone is efficient to collect coarse rather than fine particulate size fraction. In this regard, a study was carried out to determine the effect of creating more negative pressure at the storage hopper of a 100 mm diameter laboratory scale cyclone. The negative pressure was created by drawing out a small portion of the gas stream by means of an air pump attached to the storage hopper.  Results showed that there was exponentially related between the pressure drop (ΔP) and the amount of gas stream drawn at the storage hopper, but with an increment of 2.6% with suction compared to without. Interestingly, it was observed that more of the fine particulate matter was drawn from the gas stream as the suction flow rate increases. This is due to the suction velocity which exceeds the terminal falling velocities of the fine particles size range. There was a reduction by weight in the fine particle emitted from the cyclone ranging between 14% to 52% by introduction of the suction. The finding serves as a basis for future work in reducing fine particulates from a cyclone separator.


Author(s):  
J. L. Brimhall ◽  
H. E. Kissinger ◽  
B. Mastel

Some information on the size and density of voids that develop in several high purity metals and alloys during irradiation with neutrons at elevated temperatures has been reported as a function of irradiation parameters. An area of particular interest is the nucleation and early growth stage of voids. It is the purpose of this paper to describe the microstructure in high purity nickel after irradiation to a very low but constant neutron exposure at three different temperatures.Annealed specimens of 99-997% pure nickel in the form of foils 75μ thick were irradiated in a capsule to a total fluence of 2.2 × 1019 n/cm2 (E > 1.0 MeV). The capsule consisted of three temperature zones maintained by heaters and monitored by thermocouples at 350, 400, and 450°C, respectively. The temperature was automatically dropped to 60°C while the reactor was down.


Author(s):  
A. Legrouri

The industrial importance of metal catalysts supported on reducible oxides has stimulated considerable interest during the last few years. This presentation reports on the study of the physicochemical properties of metallic rhodium supported on vanadium pentoxide (Rh/V2O5). Electron optical methods, in conjunction with other techniques, were used to characterise the catalyst before its use in the hydrogenolysis of butane; a reaction for which Rh metal is known to be among the most active catalysts.V2O5 powder was prepared by thermal decomposition of high purity ammonium metavanadate in air at 400 °C for 2 hours. Previous studies of the microstructure of this compound, by HREM, SEM and gas adsorption, showed it to be non— porous with a very low surface area of 6m2/g3. The metal loading of the catalyst used was lwt%Rh on V2Q5. It was prepared by wet impregnating the support with an aqueous solution of RhCI3.3H2O.


Author(s):  
E. B. Steel

High Purity Germanium (HPGe) x-ray detectors are now commercially available for the analytical electron microscope (AEM). The detectors have superior efficiency at high x-ray energies and superior resolution compared to traditional lithium-drifted silicon [Si(Li)] detectors. However, just as for the Si(Li), the use of the HPGe detectors requires the determination of sensitivity factors for the quantitative chemical analysis of specimens in the AEM. Detector performance, including incomplete charge, resolution, and durability has been compared to a first generation detector. Sensitivity factors for many elements with atomic numbers 10 through 92 have been determined at 100, 200, and 300 keV. This data is compared to Si(Li) detector sensitivity factors.The overall sensitivity and utility of high energy K-lines are reviewed and discussed. Many instruments have one or more high energy K-line backgrounds that will affect specific analytes. One detector-instrument-specimen holder combination had a consistent Pb K-line background while another had a W K-line background.


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